What Causes Indoor Paint to Crack?

Poor Adhesion

• If the paint is unable to stick to the surface, it will eventually crack and peel off. Poor adhesion occurs when the surface is not prepared properly. Surfaces need to be clean, since dirt and crease can cause paint to crack. Applying paint to a glossy surface without the use of the proper primer can also cause cracking. If, for example, latex paint is applied on top of oil-based or alkyd paint, cracking occurs.

High Moisture

• Moisture is a major reason that paint can fail. Too much moisture can be caused by poor ventilation in kitchens, bathrooms and other areas where water use increases the humidity levels. Moisture problems can also develop if you paint over a layer of paint before it has time to dry or if the humidity is too high. When this happens, the paint bubbles when the moisture evaporates. Always wait the minimum time, known as the "recoat time," before painting a second layer of paint and paint when the relative humidity is below 50 percent.

Bad Application

• Applying paint under the wrong conditions will also cause it to crack. If the temperature is too high or if the sun hit the area shortly after it was painted, the paint may have dried too quickly. Paint that dries too fast does not adhere as well. Waiting too long to paint can also cause cracking. Some primers have a "maximum" or "critical" recoat time that is the longest you can wait before painting it. If you apply paint after this time, it doesn't adhere to the primer.

Older Homes

• Paint that has built up or is too thick will crack. This often occurs in older homes where surfaces has been painted and repainted. This may cause cross-grain cracking (crazing) or alligatoring. Older homes built in the late 1800s and early 1900s sometimes have walls that were painted with calcimine. This is a powdery substance that, unless it is removed, will cause paint to crack, blister and peel.